NEW YORK (Reuters Health) - People with inflammatory bowel disease (IBD) face a significantly increased risk of influenza, according to a retrospective database study.

"While the size of that risk may not be that big, getting vaccinated every year will give patients the best chance of avoiding flu (and possibly a pneumonia or hospitalization) from it," Dr. Andrew Tinsley of Penn State Hershey Medical Center, in Hershey, Pennsylvania told Reuters Health by email.

Immune-system dysregulation like that seen with ulcerative colitis (UC) and Crohn's disease (CD) is associated with an increased risk of viral infections, and both the American Gastroenterology Association and the Crohn's and Colitis Foundation recommend vaccination against influenza. There are few data, however, on the incidence and risk of influenza and related complications in patients with IBD.

Dr. Tinsley's team used data from the MarketScan Health Claims Database from 2008 through 2011 to estimate the incidence of influenza and risk of related complications in more than 140,000 IBD patients versus the same number of age- and sex-matched controls.

The overall annual incidence of influenza was 709.5/100,000 for IBD patients (766.2/100,000 for those with UC and 650.2/100,000 for those with CD), compared to 459.7/100,000 for the matched controls, the team reports in Inflammatory Bowel Diseases, online July 18.

Compared with controls, the influenza risk was 54% higher among IBD patients (61% higher among CD patients and 47% higher among UC patients), a significant difference.

Patients with IBD also had a significantly higher hospitalization rate within 30 days of their influenza diagnosis (5.4% vs. 1.85% for controls).

In a subgroup analysis matching 2,963 IBD patients with influenza to 8,889 IBD patients without influenza, systemic corticosteroids were the only IBD medications independently associated with influenza risk, after adjustment for other factors.

"Gastroenterologists need to take ownership over vaccinations for their patients instead of presuming this falls to the primary care doctor," Dr. Tinsley said. "Find a clinic flow that will allow vaccination status to be assessed and then deficiencies addressed."

Dr. Neeraj Narula from McMaster University in Hamilton and the University of Toronto, Canada, has also researched the need for influenza vaccination in IBD patients. He told Reuters Health by email, "It was not surprising to see that IBD patients were more likely to have influenza than non-IBD patients, with steroid use being found to be an independent predictor of influenza risk. It was surprising, however, that biologics and immunomodulator use was not associated with increased risk of influenza. This, however, was a retrospective study of a large database where influenza vaccination status was not reliably recorded, so these findings are difficult to interpret without understanding vaccination use among this population."

"We previously assessed (barriers to influenza vaccination) in a Canadian study among IBD patients using immunosuppressants who declined vaccination," he said. "We found the most common reasons patients declined vaccination were fear of immediate side effects and serious complications. Fifteen percent of patients were actually not aware vaccination was indicated, which may reflect the need to further educate health care providers on the safety and need for vaccination in IBD patients using immune-suppressing therapies."

"Steroid use is a risk factor for influenza infection, and given the unpredictability of disease relapses, which may require steroid use, and the safety of influenza vaccination, consideration should be given to routine vaccination of all IBD patients, and not just those who require biologics or immunomodulators," Dr. Narula said.

Dr. Sunanda V. Kane from Mayo Clinic, in Rochester, Minnesota, who recently reviewed health maintenance in IBD, told Reuters Health by email, "For a lot of patients no one owns this responsibility, between the GI and the primary care provider if there is one. In addition, patients think that because they are immunosuppressed they should not get a flu shot, which is the opposite of the truth."

"Remind your patients that they can prevent a serious illness by getting vaccinated," said Dr. Kane, who also was not involved in the new study.